Chapter 9: Cellular Respiration and Fermentation

Question 1

Fermentation

Answer 1

• Catabolic process that makes a limited amount of ATP from glucose without an electron transport chain
• Produces a characteristic end product (i.e. ethyl alcohol or lactic acid)

Question 2

Aerobic Respiration

Answer 2

• Catabolic pathway for organic molecules
• Uses oxygen as the final electron acceptor in an electron transport chain
• Ultimately produces ATP
• Most efficient catabolic pathway
• Carried out in most eukaryotic cells and many prokaryotic organisms

Question 3

Cellular Respiration

Answer 3

• Catabolic pathways of aerobic and anaerobic respiration

- Break down organic molecules and use an electron transport chain for the production of ATP

Question 4

Redox Reaction

Answer 4

• Chemical reaction involving the transfer of one or more electrons from one reactant to another
• Short for reduction-oxidation reaction

Question 5

Oxidation

Answer 5

Complete or partial loss of electrons from a substance involved in a redox reaction

Question 6

Reduction

Answer 6

Complete or partial addition of electrons to a substance involved in a redox reaction

Question 7

Reducing Agent

Answer 7

Electron donor in a redox reaction

Question 8

Oxidizing Agent

Answer 8

Electron acceptor in a redox reaction

Question 9

Electron Transport Chain

Answer 9

Sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP

Question 10

Glycolysis

Answer 10

• Series of reactions that ultimately splits glucose into pyruvate
• Occurs in almost all living cells
• Serves as the starting point for fermentation or cellular respiration

Question 11

Citric Acid Cycle

Answer 11

• Chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules to carbon dioxide
• Occurs within mitochondria
• Second major stage in cellular respiration
• Also called the Krebs Cycle

Question 12

Oxidative Phosphorylation

Answer 12

• Production of ATP using energy derived from the redox reactions of an electron transport chain
• 3rd major stage of cellular respiration

Question 13

Substrate-Level Phosphorylation

Answer 13

Enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism

Question 14

Acetyl CoA

Answer 14

• Acetyl coenzyme A
• Entry compound for the citric acid cycle in cellular respiration
• Formed from a fragment of pyruvate attached to a coenzyme

Question 15

Cytochrome

Answer 15

Iron-containing protein that is a component of electron transport chains in the mitochondria and chloroplasts of eukaryotic cells and the plasma membranes of prokaryotic cells

Question 16

ATP Synthase

Answer 16

• Complex of several membrane proteins that provide a port through which protons diffuse
• Functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP
• Found in the inner mitochondrial membrane of eukaryotic cells and in the plasma membrane of prokaryotes

Question 17

Chemiosmosis

Answer 17

Energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP

Question 18

Proton-Motive Force

Answer 18

• Potential energy stored in the form of an electrochemical gradient
• Generated by the pumping of hydrogen ions across biological membranes during chemiosmosis

Question 19

Alcohol Fermentation

Answer 19

Glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD+ and releasing of carbon dioxide

Question 20

Lactic Acid Fermentation

Answer 20

Glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide

Question 21

Obligate Anaerobe

Answer 21

• Organism that only carries out fermentation or anaerobic respiration
• Such organisms cannot use oxygen and may in fact be poisoned by it

Question 22

Facultative Anaerobes

Answer 22

Organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present

Question 23

Beta Oxidation

Answer 23

Metabolic sequence that breaks fatty acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA